It fluctuates depending on how far up its own behind the central bank has its head, but usually isn't too bad - it can stretch out to ~1.5x while the official "market" is in denial, but usually stabilises at about 1.2x to 1.3x depending on currency and source.

I've settled on maintaining a domiciliary bank account (denominated in USD) - SWIFT transfers take a few business days, but that's not a problem for steady income and clients can usually be persuaded to eat or split the fees. Plus it's easier to tell people I prefer to receive and hold USD than to explain the state of the economy. Also WorldRemit recently added same-day direct-to-bank deposits of USD in Nigeria-based USD-denominated accounts; I've only received money that way a couple of times though.